1.144 class shadow

A shadow object describes a drop shadow, as the CSS property box-shadow does. It is the shape of a graphical, moved by shadow<-x_offset and shadow<-y_offset, grown by shadow<-spread, blurred over shadow<-blur pixels and painted in shadow<-colour, which normally has an alpha so the background shows through. The shadow is painted outside the area of the graphical, which keeps its size, and not under the graphical itself, so it also shows correctly for a graphical without fill.

The classes box, ellipse, circle and figure have a shadow<->shadow:

send(Box, shadow, new(_, shadow))
send(Box, shadow, new(_, shadow(0, 6, 16, colour(@default, 0, 0, 0, 110))))

For compatibility, shadow->shadow also accepts an integer N, which is a soft shadow N pixels to the bottom right, blurred over 2N pixels in the default colour, and 0, which removes the shadow.

A shadow with a large shadow<-blur is drawn by blurring an image of the shape and thus takes more time to paint than the shape itself.

1.144.1 Instance variables

shadow <- x_offset: int

Horizontal distance from the shape. Positive is to the right.

shadow <- y_offset: int

Vertical distance from the shape. Positive is down.

shadow <- blur: 0..

Width of the blurred edge. As in CSS, the edge is blurred with a Gaussian blur with a standard deviation of half this value. 0 gives a sharp edge.

shadow <- colour: colour

Colour of the shadow. Use a colour with an alpha, e.g., colour(@default, 0, 0, 0, 80).

shadow <- spread: int

How much larger (or, if negative, smaller) the shadow is than the shape.

1.144.2 Send methods

shadow ->initialise: x_offset=[int], y_offset=[int], blur=[0..], colour=[colour], spread=[int]

Create a shadow. Arguments that are not given come from the class variables of the same name: 0, 3, 8, colour(@default, 0, 0, 0, 80) and 0, a soft shadow below the shape.

1.144.3 Get methods

shadow <-convert: int -> shadow

An integer N is a soft shadow N pixels to the bottom right: shadow(N, N, 2*N).